Polyprobe will optimize DNA dendrimers for signal enhancement in nucleic acid hybridization assays. Dendritic DNAs yield over 100 fold improved sensitivity in conventional hybridization techniques. DNA dendrimers will be incorporated into in situ hybridization via oligonucleotide-fluor conjugates. DNA dendrimers of about 18kb MW are readily detectable as individual molecules, therefore these reagents are ideal for non-isotopic protocols, such as fluorescent and enzyme mediated detection. The individual molecule detection capability combined with the specificity conferred by nucleic acid detection and localization of in situ techniques provide unprecedented power for molecular elucidation of biological phenomena. The Southern blot remains the choice for individual identification (DNA fingerprinting, determination of parentage, and genetic screening (muscular dystrophy, Huntington's chorea, cystic fibrosis, etc.). DNA dendrimers will be used commercially wherever signal enhancement is desired. PROPOSED COMMERCIAL APPLICATION: DNA dendrimers can be incorporated into standard hybridization assays. In situ hybridization techniques will benefit from improved sensitivity. DNA dendrimers will be used for the determination of viral load and thereby will improve antiviral drug development.